Trust Goes Both Ways
by GoldGuardian2418
Summary: After Frisk freed everyone, Chara and Asriel were restored too, but Chara, knowing Sans remembers that she caused a lot of trouble in the Underground, is scared of the hoodie-wearing skeleton. Can Sans help her? Post Pacifist Route. Tickle story! :) No flames please.


**Okay, this story bit me hard the other day and just wouldn't let go. ;)**

 **Undertale belongs to Toby Fox. I own nothing.**

 **A/N: In this story, Asriel and Chara were just spirits trapped in the Underground, but when Frisk broke the barrier, their real forms were restored and they were reunited with Toriel and Asgore.**

* * *

 **Trust Goes Both Ways**

Frisk and Asriel were having a blast going through some of the last boxes and unpacking their stuff. Frisk had broken the barrier for the monsters a couple weeks ago and all the monsters from the Underground had settled into their new homes on the surface, and to the monsters surprise, there wasn't as much prejudice as they thought there'd be. Most of the humans were very understanding and they outnumbered the humans that were against the monsters.

Now, Chara opened the last box and the three of them finished setting up their new room. They had unanimously selected to share a room, to Toriel's surprise and happiness. The former queen had forgiven her husband after Frisk had saved Asriel and Chara and Asgore had been so happy to have his children back that he doted on them and Toriel every day and even included Frisk as well, which surprised the young girl, and she was even more surprised when Asgore had called her his daughter too.

A flash of blue appeared and while Frisk and Asriel turned and glomped the skeleton who had just arrived, Chara flinched, staying by her new bed.

Sans, who had come by to check on the three of them, had been noticing Chara flinching a lot whenever any of the monsters besides her mother and father would be near her. When Frisk had freed Chara, Sans had only know the red-eyed girl to be the one that would cause trouble for Frisk and he hadn't liked it. He even kept a close eye on her and Chara knew if she stepped out of line, she'd be in trouble with him.

But Frisk had felt everyone deserved a second chance and had asked Sans to give Chara a chance to earn his forgiveness. The red-eyed girl had already earned her mother's, father's, brother's, and Frisk's forgiveness, since they were the only ones beside Sans who knew what she had done, but Sans was reluctant to forgive so easily. But then, Frisk made him promise to give Chara a second chance and as much as he hated making promises, he promised Frisk he'd do so.

Now, Chara was looking at him with a fearful expression, not daring to even move as he was in the room. Frisk and Asriel were still hugging Sans happily and he returned their hugs. "Toriel's making some butterscotch pie," he said. "And Paps is making that pennies from Heaven you mentioned the other day, Frisk."

The young girl perked up happily at that and Asriel looked interested. "What's pennies from Heaven?" He asked.

"It's elbow macaroni and cheese with hot dogs in it," Frisk said excitedly.

"Frisk? Asriel?" Asgore called out to them, making them turn to the bedroom door to see their father smiling at them. "I have something for you two for the garden."

They immediately went up to him, but then turned to see Chara hadn't moved from her spot. "Come on, Chara," Asriel said encouragingly.

"Actually, kiddo, I need to have a talk with your sister," said Sans. "I've been sensing something wrong and it's time I got to the _bones_ of it."

Frisk giggled a little at the pun, as did Asriel while Asgore gently shook his head with a smile. Chara looked at her father hopefully, but he nodded to Sans. "Toriel told me," he said.

"Daddy?" Chara whimpered.

Asgore looked at his eldest daughter. "You need to talk with Sans, sweetheart," he said reassuringly, going over to her and gently squeezing her shoulder before he picked up Frisk and Asriel and carried them out to the garden beside the house.

Chara would have run after him, but seeing Sans standing beside her bed now made her scoot back a bit, huddling into a ball. The skeleton cocked an eyeridge at her, which made the young girl even more afraid.

"Chara, come here," he said in a level tone that held a note of sternness in it.

He was rather surprised when she scrambled off her bed, almost tripping as she was quick to obey. Too quick. Sans now knew without a doubt that Chara wasn't just doing as she was told out of obedience.

She was downright scared.

Chara stood in front of him, looking up at the skeleton with her red eyes filled with fear. "Yes, Sans?" She asked in a small voice.

Feeling her fear of him was because she had seen how terrifying he could be when angered, he decided to test that theory and his left eye sparked with the familiar flaming blue iris that was part of his powers.

The young girl flinched so hard that she almost fell over, but caught herself in time and stood before him, not daring to move. Sans sighed. "Chara," he said, and she flinched again and he noticed that she was trembling a little. The skeleton reached his hands forward, again noticing the young girl flinch as his hands rested on her sides and he picked her up, sitting her down on her bed. "Kiddo, stop flinching like that," he said gently.

"S-Sorry," she whimpered.

He sighed again. "Chara, I need you to tell me why you're acting like this," he said. "Why you're acting so jumpy around me."

She knew he'd see through her if she lied. "I'm just…making sure I do as I'm told," she said softly.

"By acting like I'm going to hit you if you don't instantly obey?"

She flinched at that and looked up at him. "I'm sorry," she said, hoping to appease him with an apology. "I'm sorry. I'll do better."

Sans shook his head. "Chara, you don't trust me, do you?" He asked her.

Chara looked at him in confusion. "Um, what do you mean?" She asked curiously.

The hoodie-wearing skeleton decided to sit by her and she tried not to move away in fear. "Kiddo, I've been noticing that since Frisk freed all of us and I promised her I'd give you a second chance, you've been really watching yourself around us, especially me," he said. "Whenever Frisk and Asriel have you join them, you always look at me first as if asking for permission and I've noticed how you've declined a few times."

She sighed a little. "I just…didn't want to…step out of line," she said softly.

Sans cocked an eyeridge at her. "Kid, why do you think playing with your siblings is stepping out of line?" He asked.

Chara felt tears fill her eyes. "Well…I…I really don't know," she admitted. "I…guess I wanted to make sure you approved? That it was okay with you? That you…wouldn't be mad at me? Especially after…I tried to get Frisk to…do a genocide route."

The skeleton had a thought. "You were watching my reactions, hoping I wouldn't get mad at you," he said in realization.

She flinched a bit, but nodded as he hit the nail on the head. "Sorry," she said softly, tears gathering in her red eyes.

Sans let out a breath and nodded. "Kiddo, trust goes both ways," he said gently.

Chara looked at him curiously. "What do you mean?" She asked.

He placed a gentle hand on her shoulder. "You have to trust that I'm giving you a chance to earn my trust," he said gently. "I made a promise to Frisk and I'm not going to break it. I'm giving you a chance to earn my forgiveness and trust, Chara, but you have to believe that and trust that I'm not going to hurt you."

She looked up at him. "But…what if I do step out of line?" She asked. "What would you do?"

"Do what I do with Frisk when she gives me an attitude about something," he said. "Give her a stern warning first and if she continued, tell Toriel and let her decide Frisk's punishment," Sans said.

Chara looked confused. "But…I thought you were Frisk's dunkle," she said.

"I am," he said. "But I often lean towards the 'uncle' part more than the 'dad' part."

"While Daddy takes on the role of 'Dad' for Frisk, right?" Chara asked.

"Right," he said. "But back on subject. I don't want you acting afraid of me, Chara. Do you know why?"

She thought for a moment. "Because it means…that I'm…not trusting you?" She asked curiously.

Sans nodded. "Right," he said again. "So, do you understand?"

The young girl nodded. "Yes," she said. "I'm sorry, Sans."

"You didn't do anything wrong," he said. "So you don't need to apologize."

"But…,"

"No buts," he said. "Or I'll have to use extreme measures to get you to quit apologizing for nothing."

Hearing the skeleton's voice become playful, Chara looked up at him. "What extreme measures?" She asked curiously.

Sans chuckled. "Well…I might have to… _knead_ these knees!"

Chara jumped slightly at that and let out a squeaky giggle as two bony hands gently squeezed and wiggled into her knees. "Or perhaps _tenderize these ribs,"_ Sans said, his fingers wiggling mercilessly into the little girl's ribs now.

She began laughing harder now. "NOHOHOHOHOHOHOHOHO!" She pleaded with him.

The hoodie-wearing skeleton smirked at seeing Chara trying to get away, but he didn't let her get away from him.

" _Little Baby Bones creep softly,_

 _Eyes wide and brightly looking,_

 _Watching for the tickle monster,_

 _But he sees them and follows."_

Hearing him speak those words, the young girl looked at him curiously as Sans lifted her up into his lap, holding her in a protective, secure embrace as he continued speaking.

" _Clutching a small blanket tight,_

 _Little eyes looking, watchful,_

 _Suddenly, they softly trip,_

 _And eager fingers wiggle into little ticklish feet."_

Noticing her feet were bare, Chara tried to squirm, but Sans gently pinned her legs with one arm and tickled her feet briefly, making her giggle again.

" _Baby Bones run quickly,_

 _Dropping the blanket that long fingers pick up,_

 _A form emerges with a big smile,_

 _Ears hoping to hear a child's sweet laugh,_

 _He follows softly after the little one."_

" _Little Baby Bones glance around,_

 _But sees nothing,_

 _Although they hear a noise,_

 _And see long fingers coming towards them."_

The skeleton now wiggled his fingers teasingly at her, which created instant giggles from her as she recognized the same playful look he'd give Frisk when he was tickling her. She began to feel better as she finally felt her anxiety leave her. Sans noticed this and his smile grew.

" _Seeing the little one move away,_

 _He smiles and follows still,_

 _Knowing soon the child will be laughing,_

 _As on their tickle spots his fingers will dance._

" _Baby Bones hear words indistinguishable,_

 _Yet they are gentle to hear,_

 _Pausing for a brief moment,_

 _Long fingers gently poke their sides and ribs."_

Chara giggled, squirming around as her ribs and sides were tickled again playfully, even scrunching up her neck into her shoulders when Sans gave her neck a brief tickle.

" _Moving away again, Baby Bones is thirsty,_

 _And goes to the kitchen,_

 _Turning on the light to expose the tickle monster,_

 _But finds the tickle monster there with a friend."_

" _Trapped, the child looks up in fear,_

 _Only to feel gentle fingers tickle their sides,_

 _Before tickling fingers tickle the child's stomach."_

Her loud giggles filled the room and turned to laughter as her stomach and sides were mercilessly tickled and she tried to protect her stomach, because it was one of her weakest spots, but that didn't deter the tickling fingers that continued to tickle her.

" _The tickle monster smiles again,_

 _Hearing such a sweet sound,_

 _Gently tickling little Baby Bones,_

 _Until seeing little eyes look sleepy._

" _Baby Bones feels their blanket surround them,_

 _As arms as gentle as the tickling fingers,_

 _Hold them while letting them get a drink of water,_

 _And then carrying them back to their room._

" _Before tucking them in,_

 _The tickle monster has one more trick,_

 _Blowing raspberries into Baby Bones' tummy,_

 _And tickling ticklish toes gently."_

Sans decided to give Chara a breather and she tried to catch her breath as she tried to squirm away, but he shook his head at her. "Ah, ah, ah," he said, pulling her back into his lap. "You're not escaping this tickle torture before I'm done with you, you little wiggle worm."

His playful tone and words made her giggle again before she squealed when he suddenly blew a raspberry into her stomach and repeated the action several more times before wrapping and arm around her ankles and tickling her feet, especially right under her toes.

"HEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEEHEE!" Chara giggled crazily. "SAHAHAHAHAHAHAHAHAHAHAHAHAHAHAAHANS!"

He laughed in amusement as he nodded, seeing she had had enough and stopped, watching her recover as he finished the story.

" _Last, but not least, as the tickles end,_

 _A sleepy little head nods a little,_

 _Baby Bones hold out little arms,_

 _Which the tickle monster sees and smiles."_

" _Again, gentle arms surround and hold,_

 _As soft words are said in little ears,_

 _Little eyes on an angel's face close,_

 _Knowing they have found a true friend."_

Chara suddenly sat up. "Wait, I've heard that before," she said. "That…That tall skeleton. Gaster."

Sans nodded. "He's at the lab with Alphys," he said. "He came up with that story long ago."

The red-eyed girl smiled before looking a bit worried about something. "Sans…um…do you think I could ask Alphys to…work on my eyes to make them…not red?" She asked.

The skeleton looked a bit surprised. "Why would you want to do that?" He asked. "Your eyes are part of you, kiddo. Why do you want to change them?"

Chara sighed softly. "Because…I…I want to be accepted and not judged by others," she admitted.

"But kiddo, didn't your mom and dad accept you? What about Asriel? And Frisk?"

She had to admit he made a point and felt him gently tilt her chin up a little to look at him. "We accept you, kiddo," he said gently.

The young girl looked up at him. "Are you just saying that to _lift my spirits,_ or do you really mean that?" She asked.

"Both, because you've been _down in the dumps_ for too long. You're way overdue for a _pick-me-up."_

She giggled at his puns, which made him chuckle as he picked her up, holding her in the same loving, protective way he held Frisk and Chara snuggled into the hug. "Um, Sans?" She asked.

"Yes?"

"Can…Can I call you Dunkle too?"

Sans smiled. "You bet, baby bones," he said to her.

She looked curious. "I thought that was Frisk's pet name," she said.

"Who says he can't call you the same pet name?" Frisk asked, smiling as she came into the room and Sans picked her up.

"My two little baby bones," he said fondly as he carried both girls downstairs and saw Asgore and Asriel in the living room. Toriel came out to announce dinner was ready. "Well, you two ready to eat? Or are your tummies _full of giggles?"_

The two giggled as Sans set them down and gave their stomachs a brief, playful tickle before letting them take their seats at the table to eat. He noticed Chara chose to sit beside him and smiled, seeing she was trusting him more, which was good because in his book, she was well into his good graces, which meant she'd soon earn his trust.

After all, trust went both ways.

* * *

 **The tickle story Sans tells Chara is one I came up with. :)**

 **Please leave a review, but no flames! I accept constructive criticism, but no hurtful remarks.**

 **GoldGuardian2418**


End file.
